Reamer having detachable blades.



G. B. CHADWICK.

- REAMER HAVING DETACHABLE BLADES.

APPLICATION FILED rss. 24. ms.

1 ,21Q9U3 Patented J an. 2, 1917.

mm- (ml/ WW GEORGE B. CHADWICK, OF PORTSMOUTH, NEW HAMPSHIRE.

BEAM-ER HAVING DETACHABLE BLADES.

Specification of Letters Patent.

Application filed February 24, 1916. Serial No. 80,292.

in the reamer, eight being shown, although the precise number is immaterial. The en largement 3 is also provided on its rear face with a like number of rearwardly-extending projections 6, each of which is located at the bottom of one of the notches 4 and has its rear face 7 slanted inward and forward, its outer face being preferably flush with the bottom of the corresponding notch. On the mandrel 2 is mounted a cylindrical shell 8 provided externally with longitudinally-extending radial grooves 9-which correspond in number, width and position with the notches4 but are enough deeper than the latter to receive the projections 6, so that the front end of the shell is adapted to abut against the rear face of the enlargement 3 with said projections lying in the front ends of the respective grooves 9. The shell 8 is clamped in this position by means of a nut 10 mounted on a threaded portion 11 of the mandrel 2 and bearing against the rear end of said shell.

In each of the grooves 9 and the corresponding notch 4 is located one of the blades 5,'the inner portion of which is cut away at its front end to provide an angular recess 12 adapted to receive the corresponding projection 6, as shown in Fig. 2, the inner edge To all whom it may concern Be it known that I, Gnoncn B. CHADWIGK, a citizen of the United States, residing at Portsmouth, in the county of Rockingham and State of New 'Hampshire, have invented certain new and useful Improvements in Reamers Having Detachable Blades, of which the following is a specification.

This invention, which is applicable to various types of reamers, taps and similar tools having detachable blades, is particu larly intended to provide a tool of this character which will operate without danger of breakage or distortion of the blades by the strains imposed upon them when in use, even though the blades are relatively long, and also to provide an improved arrangement for adjusting the blades inward and outward to vary the effective diameter of the tool. The construction by which the foregoing objects are accomplished is particularly applicable to expansible reamers of that type in which the blades extend slightly beyond the forward end of the body of the reamer and hence are effective for reaming the entire length of a cylindrical bore having a closed bottom, and such a reamer is illustrated in the accompanying drawing, in which:

Figure 1 is a side elevation of the reamer, as preferably constructed; Fig. 2 shows the reamer partly in side elevation and partly in central longitudinal section; Fig. 3 is a transverse section on the line 3-3 in Fig. 2; Fig. 4 is a side elevation of the front end of the driving mandrel of the reamer; Fig. 5 is a rear elevation of the same; Fig. 6 shows in edge view a number of graded adjusting shims hereinafter described; Fig. 7 is a similar view showing tapering shims; and Fig. 8 is a side elevation of one of the detachable blades. I

The reamer illustrated in the drawing comprises a driving mandrel 2, having at its front end a cylindrical enlargement 3 which constitutes a unitary part of the mandrel and is provided with a number of notches 1, each of which extends radially inward from the periphery of the enlargement and also longitudinally through the latter. These notches 4 correspond in number with the detachable blades 5 employed shell 8 when the reamer is fully contracted or by one of the adjusting devices hereinafter described when the reamer is expanded. The outer edge 13 and the front edge 1a of each blade 5 constitute cutting edges, which ordinarily extend at right angles to each other, and when the blade is placed in position as above described these cutting edges project respectively beyond the adjacent faces of the shell 8 and enlargement 3. All of the blades employed, which are exactly alike, are simultaneously clamped in place by means of a concave nut 15 mounted on an externally threaded portion of the shell 8 and bearing against the slanting rear ends 16 of the several blades in the usual way.

It is well understood that in a reamer having detachable blades the several blades employed cannot be spaced equally around the body of the reamer without causing it to chatter when in use, and hence it is customof the blade being supported either by the.

ary to locate the blades at slightly unequal distances apart in a circumferential direction. It is therefore necessary, in order to cause the corresponding notches 4 and grooves 9 to register, to apply the shell 8 to the mandrel 2 in a specific position, and to facilitate the assemblin of these parts I provide a pin 17 exten ing transversely through the mandrel immediately behind the enlargement '3 and having its projecting ends so located that when they are received within notches 18' formed in the front end of the shell 8 the grooves 9 in the latter are properly positioned with respect to the notches 4, the assembled parts being held in this position by the clamping nut 15 already described.

It will be seen that when the reamer above described is in use the driving power applied to the mandrel is carried forward and transmitted to the blades at their front ends, where the heaviest duty is imposed upon them, and that the rear portions of the blades are practically free from twisting strains, since they have but little cutting Work to do ard act mainly as guides in that portion of the bore which has already been reamed by the front ends of the blades. This is an important advantage over prior reamers, in which the driving torque is applied mainly at the rear ends of the blades or indiscriminately throughout their length and has been found to result in many cases in either breaking the blades or distorting them sufliciently to prevent the reamin operation from forming a true surface. guch distortion cannot occur in the reamer above described, since the only positive force by which the shell 8 is rotated is transmitted thereto through the blades themselves, in

conju lz ction with the projections 6 and the p For the purpose of adjusting the blades radially and thereby varying the effective diameter of the reamer I provide one or more sets of shims 19 of graded thicknesses, three such shims being shown in Fig. 6. All of the shims inany one set have the same thickness and are adapted to be severally located in the grooves 9 beneath the corresponding blades 5, so that the radial tion of the latter will depend on the t ickness of the shims in the set employed in any given instance, while when no shims are in use the blades rest directly on the shell 8 and the reamer will be adjusted'to its minimum diameter. When a set of shims are located in the grooves 9 the blades are displaced rearwardly to a slight extent, owing to the engagement of. the blades with the slanting faces 7 of the projections 6, but in all positions of adjustment these projections enter the angular recesses 12 to a suflicient extent to hold the front ends of the blades in the notches 4.

osi-

will be tilted slightly with respect to the bottom of the corresponding notch 4, on which it will rest at the front end of the notch only, but the projections 6 will still be effective to hold the front ends of the blades in position as previously explained.

While I prefer to employ shims as above described for adjusting the blades, because they afi'ord rigidsupport for the inner edges of the blades and prevent any possibility of accidental variation of the adjustment when the .tool is in use, it will be understood that various other means for adjusting the blades may be employed, if preferred, without losing the advantages resulting from the abovedescribed arrangement for driving the blades, and it will also be understood that my bladedriving arrangement can be utilized to advantage in various forms of reamers and other tools having detachable blades, whether the blades have projecting front ends or not, and whether thelr inner and outeredgesare parallel or otherwise. The details of construction of the mandrel and sleeve and of the means employed for securing the blades in place can also be modified in various ways without departing from the scope of the appended claims.

I claim:

1. A tool of the character described, comprising a driving mandrel having a unitary enlargement provided with blade-receiving notches, a shell mounted on the mandrel behind said enlargement and provided with blade-receiving grooves in alinement with the corresponding notches, a set of blades located in said grooves and notches, and means for securing the blades in place.

2. A tool of the character described,-comprising a driving mandrel having a unitary enlargement provided with blade-receiving notches, a shell mounted on the mandrel behind said enlargement and provided with blade-receiving grooves in, alinement with the corresponding notches, a set of blades located in said grooves and notches, means for adjusting the'blades radially, and means for securing the blades in place. 3. A tool of the character described, comprising a driving, mandrel having at its front end a unitary enlargement provided with blade-receiving notches, a shell mounted on the mandrel behind said enlargement and provided with blade-receiving grooves in alinement with the corresponding notches,

a set of blades located in said grooves and notches and having at their front ends sponding notches,

said grooves and notches and each having a transverse cutting edges projecting beyond said enlargement, and means for securing the blades in place.

4. A tool of the character described, comprising a driving mandrel havin a unitary enlargement provided'with bla e-receiving notches and with rearwardly-extendin pro jections each located behind one 0 said notches, a shell mounted on the mandrel behind said enlargement and rovided with blade-receiving grooves in a inement with the corresponding notches, a set of blades located in said grooves and notches and having recesses to receive said projections, whereby the front ends of the blades are held against outward movement, and means for clamping the blades in place.

'5. A' tool ofthe character described, comprising a driving mandrel having at its front end a unitary enlargement provided with blade-receiving notches and with rearwardly-extending projections each located behind one of the notches, on the mandrel behind said enlargement and provided with bladereceiving grooves in alinement with the corresponding notches, a set of blades located in said grooves and notches and having recesses to receive said projections, said blades being provided with longitudinal and transverse cutting edges located respectively outside of the shell and in front of said enlargement, and means for clamping the blades in place.

6. A tool of the character described, comprising a driving mandrel having a unitary enlargement provided with blade-receiving notches and with rearwardly-extending projections each located behind one of the notches and having a slanting rear face, a shell mounted on the mandrel behind said .enlargement and provided with blade-receiving grooves in alinement with the correa set of blades located in slanting rear end and an angular recess adapted to receive the corresponding projection, means for adjusting the blades radially, and a clamping nut mounted on the shell and arranged to engage the rear ends of the blades. 7

7 A tool of the character described, comprising a driving mandrel having at its front end a unitary enlargement provided with blade-receiving notches and with rearwardly-extending projections each located behind one of the notches and having a slanting rear face, a shell mounted on the mandrel behind said enlargement and provided with blade-receiving grooves in alinement with the corresponding notches, a set of blades located in said grooves and notches and each having a slanting rear end and an angular recess adapted to receive the corresponding projection, vided with longitudinal and transverse cuta shell mounted.

said blades being proting edges located respectively outside of the shell and in front of said enlargement, means for adjusting the blades radially, and a clamping nut mounted on the shell and arranged to engage the rear ends of the blades.

8. A tool of'the character described, comrising a body portion having blade-receivmg grooves and a set of detachable blades adapted to be locatedtherein, means for adjusting the blades radially comprising sets of shims adapted to be located beneath the respective blades, the shims in each set being of the same thickness and those in the difi'erent sets being of graded thicknesses, and means for securing the blades in place.

9. A tool of the character described, com prising a driving mandrel having a unitary enlargement provided with blade-receiving notches, a shell mounted on the mandrel behind said enlargement and provided with blade-receiving grooves in alinement with the corresponding notches, a set of blades located in said grooves and notches, a set'of shims of equal thickness located beneath the respective blades, and means for securing the blades in place.

10. A tool of the character described, comprising a driving mandrel having a unitary enlargement provided with blade-receiving notches and with rearwardly-extending projections each located behind one of the notches, a set of blades having their front end portions located in the respective notches and provided with recesses to receive the corresponding projections, a set of shims of equal thickness located beneath the respective blades, and a clamping nut arranged to engage the rear ends of the blades.

11. A tool of the character described, comprising a driving mandrel having a unitary enlargement provided with blade-receiving notches and with rearwardly-extending projections each located behind one of the notches and having a slanting rear face, a shell mounted on the mandrel behind said enlargement and provided with blade-receiving grooves in alinement with the corresponding notches, a set of blades located in said grooves and notches and each having a slanting rear end and an angular recess adapted to receive the corresponding projection, a set of shims of equal thickness located beneath the respective blades, and a clamping nut mounted on the shell and arranged to engage the rear ends of the blades.

12. A tool of the character described, comprising a driving mandrel having at its front end a unitary enlargement provided with blade-receiving notches and with rearwardly-extending' projections each located behind one of the notches and having a slanting rear face, a shell mounted on the mandrel behind said enlargement and provided with blade-receiving grooves in aline- 130 ment with the corresponding notches, a set of blades located in said grooves and notches and each having a slanting rear end and an angular recess adapted to receive the corresponding projection, said blades being provided with longitudinal and transverse cutting edges located respectively outside of the shell and in front of said enlargement; a set of shims of equal thickness located beneath the respective blades, and a clamping nut 10 mounted on the shell and arranged to enga e the rear ends of the blades.

igned at Boston, Mass, this 23rd day of February, 1916.

GEORGE B. CHADWIOK. 

